通过PWM控制LED灯光的亮度，实现三档亮度的切换。 实现色温的切换，通过PWM调节白光和黄光的比例。 用stm32

首先需要连接一个LED灯到STM32的一个GPIO引脚上，然后使用STM32的PWM模块来控制LED灯光的亮度。以下是示例代码：

#include "stm32f10x.h"

#define LED_PIN GPIO_Pin_13
#define LED_PORT GPIOC

void PWM_LED_Config(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_OCInitTypeDef TIM_OCInitStructure;
    GPIO_InitTypeDef GPIO_InitStructure;

    // 使能TIM3时钟
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
    // 使能GPIOC时钟
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);

    // 配置GPIOC的Pin13为推挽输出
    GPIO_InitStructure.GPIO_Pin = LED_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(LED_PORT, &GPIO_InitStructure);

    // 配置TIM3的时基
    TIM_TimeBaseStructure.TIM_Period = 999;
    TIM_TimeBaseStructure.TIM_Prescaler = 7199;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

    // 配置TIM3的OC通道1
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 0;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC1Init(TIM3, &TIM_OCInitStructure);

    TIM_Cmd(TIM3, ENABLE);
}

int main(void)
{
    PWM_LED_Config();

    while (1)
    {
        // 三档亮度切换
        TIM3->CCR1 = 0;     // 最低亮度
        delay_ms(1000);
        TIM3->CCR1 = 499;   // 中等亮度
        delay_ms(1000);
        TIM3->CCR1 = 999;   // 最高亮度
        delay_ms(1000);
    }
}

要实现色温的切换，可以通过PWM调节白光和黄光的比例。以下是示例代码：

#include "stm32f10x.h"

#define LED_PIN GPIO_Pin_13
#define LED_PORT GPIOC

void PWM_LED_Config(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_OCInitTypeDef TIM_OCInitStructure;
    GPIO_InitTypeDef GPIO_InitStructure;

    // 使能TIM3时钟
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
    // 使能GPIOC时钟
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);

    // 配置GPIOC的Pin13为推挽输出
    GPIO_InitStructure.GPIO_Pin = LED_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(LED_PORT, &GPIO_InitStructure);

    // 配置TIM3的时基
    TIM_TimeBaseStructure.TIM_Period = 999;
    TIM_TimeBaseStructure.TIM_Prescaler = 7199;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

    // 配置TIM3的OC通道1和OC通道2
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 0;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC1Init(TIM3, &TIM_OCInitStructure);
    TIM_OC2Init(TIM3, &TIM_OCInitStructure);

    TIM_Cmd(TIM3, ENABLE);
}

int main(void)
{
    PWM_LED_Config();

    while (1)
    {
        // 色温切换
        for (int i = 0; i <= 100; i++)
        {
            TIM3->CCR1 = i;         // 白光比例
            TIM3->CCR2 = 100 - i;   // 黄光比例
            delay_ms(10);
        }
    }
}

以上代码仅供参考，具体实现可以根据具体情况进行修改。